Chafe resistance and impact resistance are really two very different things. We chose polyester over nylon for halyards because nylon stretches far too much and polyester is more chafe and UV resistant. On the other hand, anchor rodes and docklines are normally nylon, because nylon can provide much greater energy absorption. Likewise, stainless steel and Mylar (polyester) make sense for chafe protection, while a softer, more elastic polyurethane is more suited to impact protection. Where does polyethylene (milk bottle material) tape fall in this hierarchy, being both softer and far more slippery? We’ll see.
Chafe. Many of the tapes failed within a few cycles on our chafe rig, even the highly regarded ISC Race tape. On the other hand, 150 cycles did nothing more than make a polished spot one the stainless steel WearAndTear Pads and made no mark on the Mylar sail repair tapes or PSP Ant-chafe Tape. Carefully installed, they will last for years. Mylar is a strong, hard material which is very low-stretch, making it difficult to lay down smooth and wrinkle free if there are any irregularities. It is also higher in friction than polyethylene PSP Anti-Chafe Tape. In the end, the PSP Anti-Chafe tape took it, not because of low visible wear, but because of lower friction, ease application, and ding resistance. Note: we used the thinner 5 mil PSP tape on our test rigs. The 10 mil tape, installed on our test boat, performs even better, resisting heavy dings.
Anti-Chafe and Anti-Friction Tapes
| MATERIAL | STRENGTH | COEFFICIENT OF FRICTION (VS. NYLON WEBBING) |
|---|---|---|
| STAINLESS STEEL | 80,000 psi | 0.31 |
| POLYESTER (MYLAR) | 30-35,000 psi | 0.24 |
| UHMW POLYETHYLENE | 6,000 psi | 0.19 |
| POLYETHYLENE | 5-7,000 psi | 0.53 |
Friction. The coefficient of friction results (see value guide) tells the story. The PSP Anti-Chafe Tape is slick, the stainless Wear and Tear pads and Mylar tapes are similar to aluminum gelcoat, and the ISC helicopter tape is high friction. Interestingly, the reinforced Mylar was higher in friction because the fibers create ribs. We used reinforced Mylar under our mainsail clew strap for years, covering some rough spots on the boom where fittings have been removed. It wore just fine, but we switched to PSP Anti-Chafe Tape as soon as we saw the friction and chafe results. We have also installed the low friction PSP tape on the front side of the mast (faster tacks), on cockpit combings where lines were cutting into the gel coat and creating friction, and certain areas prone to dings.